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Background
Blistering of the skin can be due to a number of diverse aetiologies. Pattern and distribution of blisters can be helpful in diagnosis but usually biopsy is required for histopathology and immunofluoresence to make an accurate diagnosis.
Objective
This article outlines the clinical and pathological features of blistering skin conditions with a particular focus on bullous impetigo, dermatitis herpetiformis, bullous pemphigoid and porphyria cutanea tarda.
Discussion
Infections, contact reactions and drug eruptions should always be considered. Occasionally blistering may represent a cutaneous manifestation of a metabolic disease such as porphyria. Although rare, it is important to be aware of the autoimmune group of blistering diseases, as if unrecognised and untreated, they can lead to significant morbidity and mortality. Early referral to a dermatologist is important as management of blistering skin conditions can be challenging.
Blistering of the skin is a reaction pattern to a diverse group of aetiologic triggers and can be classified as either:
* immunobullous (Table 1), or
* nonimmunobullous (Table 2).
Separation of the skin layers leading to acquired blistering can occur due to loss of cohesion of cells:
* within the epidermis (Figure 1)
* between the epidermis and dermis (basement membrane zone) (Figure 2), or
* in the uppermost layers of the dermis.
This distinction forms the histologic basis of diagnosing many of the different blistering diseases. Clinical patterns may also be helpful and are listed in Table 3. Important features include:
* location of the blisters (Figure 3, 4)
* the presence or absence of mucosal involvement, and
* whether the blisters are tense and intact, or fragile resulting in erosions and crusting (Figure 5).
Generally however, diagnosis relies on biopsy for histopathology and immunofluoresence to make an accurate diagnosis.
Overall, the immunobullous diseases are rare (Table 1); although awareness is important as delayed diagnosis can lead to significant morbidity and mortality. Most patients will require referral to a dermatologist as diagnosis and management can be challenging.
If you see a patient with blisters it is worth asking yourself:
* Could this be an infection?
* Could this be due to a topical contact reaction or drug eruption?
* Could this be a primary skin disease with:
a) blisters as a secondary phenomenon (due to inflammation), ie....